Re: [PATCH] nvme: reject completions for requests that are not in flight

[Keith Busch <kbusch@kernel.org>]

On Tue, Nov 03, 2026 at 04:18:25PM -0300, Mauricio Faria de Oliveira wrote:
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 2d8f681079e85601a92624d196e77f1ba3ace34a..3ba0666da7be6a3de2e5f0fd50155af115b4e1f6 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -708,6 +708,11 @@ static inline struct request *nvme_find_rq(struct blk_mq_tags *tags,
>  			tag, genctr, nvme_genctr_mask(nvme_req(rq)->genctr));
>  		return NULL;
>  	}
> +	if (unlikely(blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)) {
> +		dev_err(nvme_req(rq)->ctrl->device,
> +			"completion for request %#x not in flight\n", tag);
> +		return NULL;
> +	}
>  	return rq;
>  }

Is there something special about the NVMe protocol that makes this
problem unique to it? If not, why doesn't this check go into the generic
block layer instead?